Electromagnetic element or structure.



. No Drawing.

MATTHEW A. HUNTER,

OF TROY, NEW YORK.

' ELECTROMAGNETIC ELEMENT OR STRUCTURE.

To all whomz't may concern;

Be it known that I, MATTHEW A. HUNTER, a subject of the King of Great Britain, and a resident of the city of Troy, in the county of Rensselaer and State ofNew York, have invented certain new and useful Improvements in Electromagnetic Elements or Structures; and I do hereby. declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in the elements or structures of electromagnetic machines and apparatus where a high degree of magnetic permeability and low hysteresis losses are characteristics of the greatest importance.

. The invention involves the discovery that by treating iron with a small amount of titanium and by utilizing the resulting titanium-treated iron in such electromagnetic paratus where elements or structures, a material increase in the magnetic permeability of the iron and of the structure or element can be secured, and at the same time the hysteresis losses can be considerably reduced.

The titanium-treated iron utilized in con structing the electromagnetic element or structure is produced by treating iron of high purity with a small amount of titanium. The iron may, for instance, be the high grade soft iron known commercially as Swedish iron and Norway iron, or commercial electrolytic iron, or iron alloys and steels, etc., such as transformer steel of thecharacter commonly used in electrical apgood magnetic permeability is desired.

Thetitanium used for treating the iron vmay be either pure titanium or an alloy of good grade. It is important, however, that the alloy, when used, should befree or substantially free from carbon. In amount, the titanium employed should be. very small, usually less than one-half of one per cent. The amount will vary with difierent kinds of iron, and the impurities which they contain. I have obtained excellent results by treating Swedish or Norway iron wit about one-tenth of one per cent. The treatment of iron, such as Swedish iron or Norway iron, is advantageously effected by melting the iron and titanium together in a vacuum.

-.It is found upon analysis of the treated a Specification of Letters Patent.

Application filed umber 2a, 1915. Serial No.

iron that the amount of titanium in the product is very much less than the amount I added to the iron. For best results, the titanium should be completely removed or only traces of the titanium should remain. I

. Patented May 22, 1917.

have obtained the highest magnetic permeability and a relatively low hysteresis loss where the titanium has beencompletely removed so that no traces could be found.

While I do not'desire to limit myself by any explanation of the particular action of the titanium upon the iron, one eflect seems to be that the addition of titanium materially reduces the combined carbon in the iron. The titanium appears to. combine with the carbon and to be removed therewith, so that the resulting iron is substantially free from carbon, or has its carbon content materially reduced. The amount V of titanium added should be sufilcient to effect the desired improvement in the iron without leaving more than traces or very small amounts of the titanium in the resulting product. The presence of any considerable amount of titanium in the treated iron icreases the hysteresis loss and is objection ble for this reason.

'The permeability is likewise apparently the greatest when there is no residual titanium left in the'metal. As the residual titanium increases in amount, the permeabllity pro gressively decreases. Accordingly, for this reason also, the titanium should be substantially removed so that there is no residual titanium, or so that only amounts remain. v v

It is advantageous to anneal the resulting iron after its treatment with titanium, as with other transformer iron and steel, in

traces or small order that the properties of the product may be further improved and rendered more uniform.

By treatment of Swed1sh 1ron with onetenth of one per cent. of titanium,, I have produced an electromagnetic element or structure having a maximum permeability considerably in excess of 10,000 and even in excess of 14,000. Moreover, this permeability has been obtained at a flux density of about 10,000 E. which is the common commercial working density of electromagnetic structures such as transformers. Accordingl ,at a flux density of 10,000 B. the permea ilityof the structures ofthe present in vention is much in excess of the permeability of standard transformer-iron, commercial electrolytic iron, or the silicon steel'now largely used in electrical apparatus and known-commercially as XI steel. In some cases I have obtained a maximum permeability of 16,000 at a flux density of 10,000 B.

Furthermore, in the titanium treated iron elements or structures of the present invention the hysteresis losses are materially reduced, e. 9., to below 0.007 joules per pound per cycle at 10,000 B. I have obtained a hysteresis lossas low as 0.00551 with a maximum permeability of 16,000 at a flux density of 10,000. Hence, at the normal density at which the transformer iron is worked, namely, 10,000 B., the permeability of the elements or structures ofthe present invention is considerably in advance of that of other similar structures heretofore known, so far as I am aware, while, at the same time, the hysteresis losses are materially lower than with the commercial electromagnetic structures such as have heretofore-been used.

The present invention is of general application to electromagnetic apparatus and machines in which a high magnetic permeability, and low hysteresis loss are of primary importance, whether the apparatus or machine is made up of relatively moving parts as in dynamo-electric machines, or whether the elements or parts ofthe-apparatus or machine are stationary, as with transformers, etc. p

In referring to the titanium treated iron as being substantially free from titanium and combined'carbon, I do not desire to be understood as meaning that these elements are entirely removed or absent, since traces or small amounts of either or both may be present without material prejudice to the desired magnetic properties of the material and the structure or element made of it;

and accordingly, 'I desire to be unnderstood as including such traces or small amounts of these ingredients as do not materially loss, averaging at 10,000 B., about 0.009 'to 0.013 joules per pound per cycle, but the presence of silicon makes the material hard and brittle and is detrimental to its magnetic permeability, frequently lowering the permeability, at 10,000 B., much below 5,000. The novel structures of the present invention are also characterized by a low hysteresis loss, materially lower than that of standard transformer iron, which is about 0.015 to 0.018 joules per pound per cycle, and even as low or lower than that of the XI transformer steel; while they are at the same time soft and malleable and are characterized by an improved permeability and magnetization curve, having at 10,000 B. a permeability greatly in excess of the permeability of XI steel, and even exceeding that of standard transformer iron.

What I claim is:

An electro-magnetic element or structure 'tures of this material have a low hysteresis of titanium treated iron substantially free ture.

MATTEW A. HUSTER. 

